Picture frame



FIG. 1 is a front elevational view of a picture frame showing my new design;

FIG. 2 is a top plan view thereof, the bottom plan being identical;

FIG. 3 is a right side elevational view thereof; the left side being a mirror image;

FIG. 4 is a rear elevational view thereof; and,

FIG. 5 is an enlarged cross-sectional view taken along line 5 of FIG. 1. 

The ornamental design for a picture frame, as shown and described. 